So far, each issue of Defenders (including Marvel Feature #1) has been developing a threat called Yandroth’s Omegatron, In this issue, it gets resolved.
The newly created Valkyrie tries to adapt to being a real person. But she’s still got voices in her head of Barbara Norris.
So Doc Strange suggests she talk to the most outsidery people in the Marvel Universe: Sub-Mariner and Hulk. Along the way, she recruits Namorita to be her friend. They end up finding the Omegatron, and she defeats the giant robot with the help of Namor and Hulk. It’s a little weak that a threat teased for four issues ends up being crushed fairly easily, but if you think about it, The Defenders might be the most powerful team in Marvel history: Hulk, Namor, Strange, Silver Surfer, and even Valkyrie are very, very powerful beings.
Even Namorita is along for the ride.
At the end, Namor agrees to a partnership with Strange and Valkyrie, but Hulk still wants no part of a team.